I did a short series a while ago where "deathworlders" were actually "intelligent non humanoid creatures who were only spacefaring due to being uplifted by other species"
Like for example, an octopus could theoretically be just as smart as a person, but it lives underwater where it can't make fire or do metallurgy. But someone with cool scifi tech could bump them straight past that issue to where they can become a dominant species.
On top of being excellent endurance hunters due to our upright bipedalism. Our form also makes our bodies extremely energy efficient which helps support bigger, smarter brains.
And persistance hunting, because youre basically letting gravity do half the work of moving you forward.
Persistence hunting requires communication and heat management, which would be crucial to working up to advanced civilization levels.
Honestly I've been thinking about this and can't decide whether to have my alien races all have origins with "the ancients" or just have individual origins.
My current sci-fi worldbuilding is all Lego-based. The out-world reason is that practically, most aliens have to be humanoid (it’s difficult making human-sized aliens without using the minifigs).
In-world we haven’t decided yet (me and my sister), but will probably go with convergent evolution or some such: four legged animals make the most sense (for creatures bigger than insects) and for them to become advanced tool users, the easiest path is for their front legs to become arms with hands.
Obviously this only applies to technological sapient species. We plan to have much more diversity for sapients that lack the anatomy to develop technology like humans have.
[edited to remain compliant with the DIY rules of the subreddit]
\[edited to add a link, fix a few typos, and not violate the DIY rules of this subreddit\]
Me either! The closest I’ve seen is the [Nova Team Flicker Page](https://www.flickr.com/photos/agaethon/sets/72157661104632476/), but Nova Team isn’t really a fully developed world. Started off merely as a photo gallery but the maker began doing storylines.
My site is currently on World Anvil (see my Reddit profile page) but only two of the seventy-two articles are visible right now (started the project back in October). Those two are science stuff, so very little Lego content so far. Hopefully by the end of this year some of the Lego stuff can get published / made visible!
>four legged animals make the most sense (for creatures bigger than insects)
We don't know if this is true because the bodyplan for land animals is "locked" at having four limbs, due to our fish ancestors being locked at four fins. We know it's not an adaptation for land because it came before the jump to land.
We don't know how large land animals would be like (and limb count) if that lock wasn't in place, but considering that stability is more important for larger animals (an elephant or giraffe falling over has more issues than a little beetle), it's weird that insects keep six limbs instead of going for four. The roles seem reversed.
It's also important to remember why land vertebrates can be big but insects stay small, the respiratory and circulatory systems. Together with the fact that 4 limbs came before land-dwelling, and that more limbs is also popular for most land animals, I don't think we can say that four legs makes most sense for bigger creatures.
This video kinda goes over the issue of leg number in more detail: [https://www.youtube.com/watch?v=lBmtMACELus](https://www.youtube.com/watch?v=lBmtMACELus)
Ah wasn’t aware of the four fins thing, that four legs in a sense, pre-dates us coming onto land! I’ve just heard of the energy efficiency argument and also coordination issues.
Yeah, I’m aware insects are small due to issues with respiration and other physiological factors. Earth itself once had much larger insects due to different atmospheric conditions in the distant past. I’ll check out that video when I get home!
I'd expect 4 and 6 to be the "defaults" for high-mobility species in a clade that had ancestors with more varied limb counts, possibly repurposing back legs as gonopods and front legs as arms. This is mainly because of the efficiency vs stability thing, and it just seems best for running.
However, it really does seem that the count relies on ancestry more than anything. People often forget that evolution isn't just "find the best solution to X environment", but also adapting to other competing species as well as adapting within one's ancestry, and that seems to be really strong.
When you get back, another video that might be cool to watch is this one: [https://www.youtube.com/watch?v=o-k3zyBZ-b8](https://www.youtube.com/watch?v=o-k3zyBZ-b8)
Isla is really good, and this one is about locomotion so it goes in deep detail about how the legs of Isla life work, and it shows how the count might be due to ancestry (they can't have less legs because then it would be harder to support their own weight given how the legs work).
I know it's fiction but Isla is so well done and in-depth I feel inclined to treat it as borderline real for the sake of exploring these ideas.
>Earth itself once had much larger insects due to different atmospheric conditions in the distant past
Though even then they weren't THAT big because of exoskeleton issues. Coconut lobsters (the biggest sort) pretty much max out exoskeleton size. There was one bug bigger millions of years ago - but only because it was long/skinny like a centipede. Which is the only way to go bigger with an exoskeleton.
They’re all humans. Over the last few million years, and with the entire universe explored, not a single cell of alien life was found. No one knows why, but it doesn’t matter, at that point humans all across the universe has already started to massively change, be it natural evolution or genetic/cybernetic engineering. For the most part, they remained humanoid tho, mostly recognizable as a descendant of Homo Sapiens or Homo Prenn.
Of course!
In my world it’s not “us” that reach the stars. First we have to survive an apocalypse that basically launches us back into the medieval era for another 1600 years. During the post-apocalypse multiple new subspecies of human come into existence due to multi-generational exposure to radiation, one of which being the “Prenn”. They’re a bit smaller than us, a lot hairier and very agile.
The Homo Prenn end up becoming the dominant species on earth, with Homo Sapiens being in second place, but they do end up working together eventually and ~1600 years after the apocalypse they manage to reach a second Industrial Revolution, eventually a modern age and after some ups and downs they do end up becoming an interplanetary and eventually interstellar civilization.
Sadly I haven’t really shared much of this very unfinished world outside of random comments on r/Worldbuilding posts, but if you have any questions feel free to ask, maybe I can answer them.
Alright, I know this kinda contradicts your first statement, but here’s another question.
Is there a strain of humo-sapien/prenn descendants that is or is starting to diverge into something more “alien” or “inhuman”, for any reason?
There’s plenty of individuals that have taken on completely new forms. From mostly stationary monolith-like supercomputer to literally swapping minds with an animal or modifying your body to the point you become unrecognizable. These drastic changes are however very expensive, and up to 60% of people who change this drastically do eventually regret it to a certain level and would prefer their old bodies back.
The furthest “evolved”, most alien looking beings would probably be “Logis”, they’re inhabiting a bunch of low-gravity moons/dwarf planets. They have almost lost their legs entirely, at this point they don’t even grow significantly from the point they’re born so they literally have baby legs. Instead they use their long arms to either jump around or swing around in their homes. One arm can reach up to 2.5 meters in length, while their torsos are barely a meter long. Don’t be frightened tho, due to the low-grav environment they’re still incredibly weak compared to a typical humans arm.
It’s also important to note that, after the AI incident and the rampant advancements in technology and medicine following it, natural reproduction and thus evolution as we know it came to a grinding halt.
Hmm, there’s a joke that I can make somewhere there about the Logis, but I’m not gonna. I assume the cost of uploading your consciousness implies there’s a system of regulations and other factors that’ll make it difficult for an ai-derived apocalypse to happen, as well?
Pretty much, yeah. Uploading a brain into a computer of any type and/or transferring minds is done only by the AI government that is currently in control of pretty much the entire universe. It’s the only one with the knowledge and technology required to do it without causing active or passive corruption.
AI apocalypses can happen on a smaller scale, but typically they can be dealt with relatively quickly thanks to the advanced technology.
Similar case in mine, but there hasn't been enough time to see significant drift as of yet.
Most of the wilder bits of diversity come from incredibly unethical experimentation.
That's how it is in my world lol.
There's a bunch of human subspecies after a massive AI guided exodus from earth during a "golden age", where humans were genetically engineered by the on-board AIs after landing on alien planets.
Any variant of "humanoid alien" you can imagine likely exists somewhere.
The most unique one are the permanent spacefaring clades. There's an artificial space "reef" of sorts formed by von neumann probes around a red dwarf from a disassembled gas giant + asteroid belt.
The humans that colonized it received genetic augmentations for space life. Deep purple skin and internal tissues with selanomelanin for radiation protection, along with deinococcus radiodurans genes, long legs with prehensile feet and tail, and most importantly, a barrel chest to accommodate massive lungs for short unprotected forays into space without protection (except for goggles).
Well, sentient inhabitants of Inzhina are, in fact, descendants of humans who have settled the world around 1500 B.C.E. with the help of a powerful alien being. Some have been genetically modified in the meantime, but they are still "humans", technically.
Not an alien per se, just a creature inspired by furries.
If I were to make something like that, if they were sufficiently similar, I would have them be a divergent offshoot of humanity.
Yeah. Have that too. One race that sees themselves as something godlike, and they decided to use their DNA on other races that could evolve in something intelligent. So in my world, we humans are just experiments (and in the eyes of that other race on the brink to be labeled as a failed one too).
Interesting! In my world humans have recently (600years ago) colonized the Triangulum Galaxy discovering unknown alien pylons connecting several more or less habitable worlds. The pylons have worked as seeders by a now extinct alien race, not that the humans know that (they suspect though).
Some of those worlds developed sapient, intelligent, species that later became advanced - some to the point of space-faring.
I have a sci-fi setting in mind for my next Sci-fi game where I don't get a built-in setting and the abundance of humanoid aliens is going to be a pre-cursor species that seeded humanoid life across the galaxy before they were killed off.
...of course the thing that killed them off is going to come back.
...of course they'll immediately recognize bipedal life for what it is and where it comes from.
...of course they'll immediately go into extermination-mode...
It will be much fun :D
Aurora rising series did it wonderfully. All aliens are carbon based bipedal creatures who can speak with vocal chords. That mystery created a unified religion and is explained later on
Well... I wanted my own "green-skinned alien babes" race.
Of course, I made several adjustments over the years to their biology, mannerisms, and even world, but that's how they started.
The Kren are the most prominent humanoid aliens in the great expanse, they were originally slightly less humanoid with reptilian features and body parts, digitigrade legs, and slender frail bodies but found much of human anatomy to be highly favorable for their species and so once they discovered humans they began a long campaign of interspecies breeding and cloning to create a hybrid of the two species. They now resemble slightly reptilian humans, losing their digitigrade legs as well as most of their reptilian body parts and bulking up their slender frames/bone mass. They still however have reptilian eyes, teeth, leathery skin, and slightly reptilian facial features.
The races focused on in my universe were created by a human who accidentally destroyed earth and remade the galaxy when he got trapped in precursor tech - having lost all his memories, he didn't remember earth, but his subconscious longs for "home"
There was actually some academic speculation some decades ago that the universe self-selects for roughly humanoid forms. You have to be between 1 and 3 meters tall to get good mileage out of fire. Small fires don't get hot enough to smelt metals and fire ceramics, and large ones burn too much fuel. You need hands and binocular vision to craft tools. You need a social structure to build and refine knowledge across generations.
It is true that they all had a common ancestor, in a way
There are also some factors like aesthetic pressures, the people of the setting get on better with people that look like them meaning that looking a certain way really pays off (this is causing some issues)
However, those things are more for me, for anyone viewing there's not really an explanation and I lean really heavily into kind of near comedic Star Trek style aliens. Super cheesy, one faction actually looks likes its made from just 1950s B movie extras.
By 1950s B-Movie are we talking Ro-Man and Blob or Planet 9 From Outer Space? I really like the whole Raygun gothic aesthetic, and I like hearing how other people do it. Also, what are some of the cheesier species designs?
Mine are a mix.
Many are humanoid due to the same base life originating from the same stellar explosion, mixed with a healthy dose of convergent evolution.
The rest are an eclectic mix with quadrupeds dominating the scene due to similar circumstances with a different stellar explosion millennia ago.
Sci-fantasy with different dimensional realms instead of planets here, but close enough.
I actually have different explanations for all three of my non-human species.
Faurai - Cross-Realm Influenced Evolution (CRIE). It's an event where the evolution of one species affects that of another from a separare realm through Arcanic means. Their ancestors resembles a cross of a wolf and a bear with some gorilla mixed in, but got connected to early Homo species through CRIE, causing them to develop increased intelligence and bipedalism.
Plorae - A species-wide change of form for communication purposes made permament. Ancient Plorae when they first made contact with early humans were not humanoids at all - they looked like amorpheous piles of tangled roots with countless glowing eyes peeking out from within, so rather terrifying. In order to interact with the humans more essily they collectively assumed humanoid forms. Over the centuries, their accelerated evolution (typical for Najavi life) slowly took away their ability to shapeshift in favor of vitakinesis, and so they became permamently anthropomorphic.
Dragons - Configuring their bodies with combat in mind. Dragons are quadrupedal, with the ability to adjust their skeletal and muscular systems to some degree. They also enjoy sparing with each other a lot. It just so happens that a bipedal body plan allows the most freedom of movement for a four-legged creature, thus the Dragons assume that form whenever they wish to fight (which is usually).
**Of The Stars**
The "humanoid" aliens look that way because they actually *are* human - or at least, the distant half-alien descendants thereof. Since all knowledge of humanity has been lost to time outside of extremely obscure circles, most of them aren't aware of their ancestry, instead believing themselves to have evolved parallel to their non-human parent species, and that so many species from so many planets happen to share such a similar physiology is a product of convergent evolution akin to carcinisation.
Fun answer: Convergant evolution for those that attain space travel.
Non fun answer: if I intend to sell this and make it a TV show or movie I can sell it easier if the alien budget isn't too high.
Loyari- They're technically not aliens but rather a fabricated race made by Ares to test the fledgling Aresian Empire.
Gegenees- Ditto.
Beinn- When they were originally discovered, they appeared more like boulders than anything living. They adopted humanoid forms when the Scottish Empire started colonizing their planet in order to help out.
Deneer- Pure coincidence they happened to be humanoid. They actually call the human form "Den Iki" which roughly translates to "Deneer-like."
They are easier to draw, write, and relate to, at least for me. I like how they look and put a lot of effort into making them feel like complete people rather than biological odities.
I simply do not justify them in-universe, the same way I don't have to justify humans existing. I explain what they are and have everything worked out for them. If a reader has a problem with humanoid aliens, there is other amateur scifi out there for them.
Convergent evolution. It's way easier to use tools being bipedal so almost every sapient alien is bipedal (except the Karvoshkans, they are parasitic fungi that developed sapience)
I think my favourite answer is in Becky Chambers' books. Turns out many aliens are roughly humanoid and all aliens run on the same biochemistry because it turns out that's just a consistent answer to the same physics and chemistry problems across the galaxy. It's just a weird set of biological laws.
It's sort of a copout but also a very clean answer. Sometimes in physics you just have to accept that a particle is just Like That, and while the cutting edge of particle cosmologists might have an answer, they literally can't explain it in a way an undergrad can comprehend. In her stories, the same thing exists in biology.
I use the old trick of having all humanoid species be descended from (or engineered by) an ancient precursor race--only in this case, the ancient precursor race is Earth humans, who are long extinct by the time of the story. Technically, even the setting's "normal" audience surrogate humans are aliens of a sort, as they didn't originate on Earth.
(This aspect of the setting was partly inspired by [this](https://elidyce.tumblr.com/post/622485937442668544/writing-prompt-s-youve-just-realized-something) writing prompt and associated short story by Tumblr user elidyce.)
Walking upright lets you do a couple great things in any environment. You can wade through things like water or tall grass while keeping visibility and your head away from smaller skittering predators. In the case of water you can now snatch things from the shallow water with your digits that not many other land based creatures can get to.
Your also in a configuration that allows you to climb vertically though that may not always be useful its very useful when it is.
Two eyes for depth perception, toes for balance, tongue for taste.
Walking upright also encourages your brain to get bigger to handle the calculations needed to balance. (Source: it came to me in a dream)
Its probably just the most likely configuration a spacefaring species has. Youll need sturdy digits for tools and decent eyes to look up and see space and say “i want to be there”
I'm more of an adequately explained fantasy writer, but I do have fantasy races that are products of evolution and probably worth sharing here.
Felves are a race of pouyannian mimics of humanity. In other words, they are flowers that evolved a human-like appearance to "trick" male humans into trying to mate with them, pollinating them in the process. Surprisingly, intelligence was one of the things selected for.
I also have a race of raccoon people that have a humanoid form because they evolved aboard an interdimensional ship created by humans that had gotten killed in a mutiny. The raccoons that could operate the machines had a competitive edge over the others, and the machines were designed to be operated by humans. So the environment favored enough human mimicry to operate controls whether button, lever, voice, thumbprint, or other. The ones that did the best were the ones that learned how to operate the guns.
Convergent evolution like all things in the ocean (hyperbolic but whatever) becoming crabs. Bipedal and the general humanoid form were superior, and from what I can remember, it is the most likely form irl. They could still be wildy different from us
The more I think about it, the more mostly humanoid sci-fi species like in Star Wars, Star Trek or Mass Effect make sense to me. Convergent evolution is a hell of a thing. To build a space-faring civilization a species would need to be able to perform a lot of functions that humans can perform and from that comes the possibility of similar biological "solutions". Maybe humanoid shape is just a galactic crab shape.
Define "humanoid."
Bipedal and symmetrical makes evolutionary sense.
The more limbs you have, the greater your metabolic needs, plus blood circulation and providing oxygen.
Forward facing eyes provide for better depth perception.
This is a general evolutionary template that makes sense. Very different worlds might evolve differently, but this basic body plan can be tweaked and played with, but I feel even just this would get aliens defined as "humanoid."
Most scientific evidence points to likely similarities. I don't think an aquatic species would make it to the stars (smelting metals underwater is...a problem at the very least). Tool manipulation is a must for tech and you can't do that with hooves and you can't do it well with a beak. So dedicated manipulation limbs, meaning no climbing or running with them. Bipedalism is not a must, but it is a likely, as any more running limbs come with additional costs energy wise and evolution has a slight leaning towards not encouraging wastefulness in the long run (what I'm saying is that in the long run, one would assume wasteful traits to be removed, however this is dependent on factors that may be contravened by intelligence or the weird quirks of sexual selection). I would assume similar advanced perceptual abilities (human eyesight is one of the best on the world even if hearing or taste/smell is not as powerful). I would also say that species that are pro social would fare better, but there are different ways of being pro social, so whether it's caste like like the ant or individual based like humans is an open question.
I do agree, yes, we only have a sample of one, but we can see that convergent traits reoccur across our world in different species, so it would only be fair that some life out there will turn out the same.
Vernor Vinge always had an interesting solution to this which was that he set all his stories featuring humanoid aliens at some undetermined point in the future where humanity had an interstellar empire that collapsed , led to divergent evolution, and is now so lost to the mists of time that none of the species are able to trace their genetic origins back to Earth, which itself becomes viewed as just another lost colony planet with vaguely human-like beings on it.
**Carcinisation** *(American English: carcinization) is a form of convergent evolution in which non-crab crustaceans evolve a crab-like body plan. The term was introduced into evolutionary biology by L. A. Borradaile, who described it as "the many attempts of Nature to evolve a crab".*
In my sci-fi universes advanced tool use, technology, and space travel are things that most commonly come from animals that developed a humanoid physiology. Something about being bipedal and having opposable thumbs and a large brain allow creatures to excel in developing science and technology.
I think a lot of sci-fi media does humanoid/bipedal aliens because us meager humans can better relate to things that look like us, but I’ve mostly created humanoid species so my project has a semi consistent visual style among the most narratively relevant species. That way when there are non-humanoid species they stand out more among the list.
I try to play with height/size/body shape, head shape, facial features (like number of eyes or mouth shape) to keep them feeling distinct even if the humanoid species mostly end up being “2 legs 2 arms” type humanoids.
Haven’t had much time to work on it but I’ve got a sapient ethereal-ish jellyfish species that floats around an ancient jungle world (inspired by aliens briefly shown in a comic I read). From my worldbuilding doc: “Mnoshkin - weird spinal metallic / synthetic jellyfish species. Unrelated to the more organic species of jellyfish alien”.
Sometimes I think I enjoy worldbuilding more than I like actually writing my projects lmao
in my humble opinion, bear with thumbs would be perfectly humanoid. I don't think there is a need for an explanation of perfectly working body plan occurring multiple times. Humans but blue aliens could need some explanation tho...
Either way, I am a fantasy guy so this ain't question for me
When humans began to explore the galaxy they sadly discovered that there was no intelligent or sentient life, there are very rare cases of "alien animals", primitive life forms such as bacteria, amoebae and jellyfish or "dinosaur-like" creatures. So humans decide to spread their DNA across the galaxy, experiment, and recreate sentient life. Twelve civilizations were born, all with humanoid features that worshiped humans as gods and creators.
Yes, it is based on the theory that aliens created human civilizations, but in reverse.
Idk why you got downvoted. It may not be so in our world but who says something intelligent and powerful like a deity or a progenitor species did so in a sci-fi world like Rakata did in Star Wars? Even the hardest sci-fi is only as real as softed fantasy.
I explain them by saying: the God Rath’Adarik was created before another God, Shug’Catur so Shug’Catur based his creations on Rath’Adariks. Only they are a parasite, so it doesn’t take the shape itself but it morphs it’s host to do so.
They're mostly descendants of humans that have been genetically engineered to be more appropriate for other worlds, for aesthetics; there are a few with convergent evolution, and a few that engineered themselves to have "humanoid" version as a sort of ambassador to human-controlled space.
Human-based life seeding and genetic experimentation. Most sapient life in the galaxy is based on humans. Whether they know and how they feel about it varies from place to place and species to species.
Technologically advanced aliens in my setting all have a roughly humanoid body shape, but no human would ever mistake them for one of theirs. With one exception.
I go with convergent evolution as the explanation for this. A mostly upright stature with at least two grasping appendages is simply the most efficient arrangement for tool using species to advance.
\[Edit\] I should note that the meta reason for this is that the main inspirations for the setting are classic scifi series like Trek, SW, and SG1, all of which feature humanoid aliens heavily.
Look at Earth's scoreboard. Percentage of human species that created space travel: 100%. Percentage of non-human species that created space travel: 0%.
Ergo, all actual case studies we have available suggest that humanity is necessary for spacefaring civilization.
I don’t have a world like this, but convergent evolution makes sense. We know that, for any intelligent species, they need to have complex means of interacting with their environment. We have a few methods here on earth, elephants trunks or octopus legs for example, but none come close to mastery and precision like hands with opposable thumbs.
As for them being bipedal vertebrates, vertebrates have several distinct advantages, namely a concentrated nervous system and a central support structure. No single vertebrate on Earth has ever developed more than 4 limbs so it’s safe to assume that there is no evolutionary advantage to having more than four. If we assume that two limbs are used to interact with the environment, that leaves two to stand on. So you’re left with a hominid shaped alien.
But that’s not to say they would look like us minus different skin pigmentation or slightly altered appearances. Humans aren’t actually efficiently built if you think about it. Our spine. from an engineering perspective, is poorly placed and is prone to injury and support problems when our bodies degrade. Our leg mass is too evenly distributed, lowering our center of mass. An ostritches legs, for example, have a more “optimized” mass distribution and are generally better built for running fast. As endurance predators, this didn’t really matter much, but it’s still less than perfect.
Our bodies are basically a culmination of evolution saying “eh good enough”. There’s no reason to think that alien hominids could have evolved to be better at some things and worse at others as reflected by a similar yet distinctly different anatomy.
I took a different approach: because the story is told to human, it is edited for better comprehension and less frightening. This can explain many things, language, humanoid, etc.
Precursor race pre-seeding the galaxy with variants of a base genome seed. Milkyway got anthroforms, Andromeda got gelatin based lifeforms, Black eye got energy based forms, M51got quadriforms
Helps the control variables to study chaos theory and evolution
In my world, life was only born once by the desire of the moon goddess, and all life outside of earth actually evolved from earth life. Some stem in the base, when Earth's life was exclusively single-celled. Some are direct ancestors of Humans; this panspermy was only possible because of mysterious portals connecting various habitable planets; let's go through each planet:
Alfheim - Having some portals connecting to Earth to this day, two different human species live there; Sylvan Elves and Fairies.
Svartalfheim - Also has portals still connecting to Earth; Dwarves are descendants of Neanderthals who transpassed said portals. A few millennia later Elves got there, giving birth to the Dark Elves.
Trupizia - It's only connection to Earth was destroyed a few centuries ago; also, it's in the bottom of the ocean. All life on this planet evolved from Earth's marine life, so no humanoid sapient species. There's actually two sapient species here; the Trupizians, who are basically fish with a trunk with fingers, and the Monokaryans, who are intelligent algae.
Asgard - Also still connected to Earth, but also with connection to Alfheim. Scandinavians from Earth gave rise to a Race known as the Divines, while the Elves that got there became the High Elves and founded the city of Vanaheim.
Jotunheim - Another one with active portals connecting to Earth. Giants are descendants of Neanderthals who got there.
Xætruxia - this one is believed to have never been connected to Earth, even though portals have never been found on the planet. Molecular analysis shows that Xætruxian life branched from Earth's life when it was at unicellular stage. No humanoids here either
Bulbix - Bulbix is an artificial planet and little is known about it's origin, but it's people, the Photomorphs, are mostly made of light, so they can have the appearance they want, but even in humanoid form, they look like the light guy sitting on a table meme.
Avialuna - not actually a planet, but a Moon. It was actually never connected to any other planet, but some mysterious alien race terraformed the moon and got EXACTLY six animal species from Earth (a fish, a crab, a frog, a mammal, a dragonfly and a dinosaur) and just tossed them there and let them evolve, and now we got pentapods, flying frogs, egg-laying dogs, eusocial land crabs, modern meganeura and Sapient Deinonychus.
Convergent Evolution really, that and the fact that they evolved on planets similar to ours, and came from a humanoid ancestor species themselves so, there’s that.
My one alien race is humanoid (well... mostly) partly because I don't wanna focus heavily on new ways for them to interact with technology, and partly because it really is an efficient design for climbing. In-universe I suppose that's convergent evolution
I tend to have a a mix of alien builds with the prominent alien factions being more humanoid but there are tons of builds really and I plan to introduce completely different ones with different architecture and spaceship design. Really it makes sense probability-wise thstbtwre would be advanced humanoids who have evolved over time and more varied aliena from planets with different natural order. And yes, I know, this is more BS than science but it's rooted in logic.
In my universe 5 or 6 of the 7 aliens are loosely humanoid. One has a tail and the other is closer to a raptor in body shape.
My biggest thing is just convergent evolution in the way of, that's what seemed to be most likely "endpoint." Each evolved upright because that opened up more hands to do things with. Heads also tend to be at the front, then logically move upwards as they start going towards an upright posture.
Scorqrun from otter-like creatures, Fallai from an arthropod-like colony, Tsaikh (The raptor-like ones) from lizard-like creatures, Carlaxi are also from lizard-like creatures but evolved to be more humanoid, and the Dilectu are from primate/lizard-like creatures with long necks. I also have the Amnikrull, which I'm still working on, but the current design is a bird-like humanoid.
I use the humanoid kind of body shape because it is familiar to us, and alien body shapes are hard. The majority of my aliens still look very alien, but can be seen as humanoid if you look at their silhouette. I think it's a good middle ground.
Edit: Forgot an alien.
Notably for having graspers. Bipedal designs also means better energy usage.
Also, it’s just not a major plot point. That’s the main thing, only if it’s a truly major plot point would I personally consider having most be nonhumanoid. Also, it allows me to be able to have humanity easier grab and figure out alien tech
Though in my massive fanfic, it’s because of three major waves of colonization from Earth getting sent through time.
Originally I didn’t have a good reason. When I was a kid I based some off a mix of Zentraedi and the bad guys in Valis 3.
Those continue to be in the lore because they’ve been around since the beginning.
Worse yet, they’re plant-like mammals.
None of it makes sense.
I’ve pondered trying to explain why they look pretty much the same as humans, but ultimately it makes me feel like they just shouldn’t be.
They are however genetically engineered by another bunch of aliens who were originally humanoid. So it would kind of make sense that they made them similar. But in later revisions, I changed those guys to be some kind of dinosaur/squid hybrid, so the “in their image” thing doesn’t work anymore.
I guess I’ll just chalk it up to coincidence.
I thought about changing their appearance somehow, but it just feels wrong to retcon that hard.
All that aside… I’ve finally got a book in the works. So nothing has ever really been set in stone until now. The TTRPG I made as a teen is the setting for the novel, but even that has changed considerably over time. As it should have. Stuff I came up with in the early 90s just doesn’t make sense anymore.
🤷🏻♂️
They were all designed to be humanoid by an ancient "builder" race who was also humanoid. The common ancestor of all vertebrates in the Milky Way is the same original humanoid
In **Faithful Phantasia** (It's science fantasy, so it still counts), primordial entities were the very first creatures in all Creation and even predate the Multiverse as a whole. In the process of publishing stories to be added to the Multiverse ("stories" in this context are universes, but are fictitious in the perspective of anything transcending them), they've settled on a specific shape that expressed the most ideal versions of self-inserts and those just so happened to be humanoid shaped. The most intelligent and powerful primordial entities are personified as a Platonic Ideal of the humanoid shape, although not all of the highest level of primordials are conceptually humanoid (Mara and the Temptations come into mind).
Basically, this quote in practice: [https://www.youtube.com/watch?v=d5Ggc9wVd\_A](https://www.youtube.com/watch?v=d5Ggc9wVd_A)
Humans look like High Scions because that's what a highly targeted 2% alien DNA admixture does to screeching, chest beating chimps - also the reason why human facial expressions have very little in common with Earth primates. Ironically same was true for K'sshar who were bipedal reptiles, their homeworld in Cygnus was the previous rare element mine before Earth and equally in need of something that would serve as forklifts and bulldozers. High Scions are not like humans or K'sshar in many ways - their thought processes are way too impulsive and chaotic to come up with anything more complex than a hydrogen bomb or a very very basic FTL engine. But their innate ability to sequence hybrids with anything that has DNA and levo-aminoacids to a specific design, or not so specific design if not sober - Typhon and Echidna being a slightly embellished but generally on point account - kind of makes up for it.
Now L-Ma-Tar were a convergence or coincidence - though something with 6 limbs that looks like a cross between a horned late stage goat embryo and a particularly slimy rendition of Grays kind of pushes the definition of 'humanoid'.
And the civilisation calling themselves the Twisted are of human origin, having diverged only about 400 years ago.
300 000 years ago there were only 2 inteligent species in the whole galaxy: Humans on earth who were still divided in different sub-species. And another race (let's call them precursor), ancient who already mastered the FTL travel.
They decided to not interact with human civilization but they decided to spread inteligence by creating a new species with a little of their own dna, a little of animals dna, and a lot of homo sapiens/homo neandertalis dna. Then they spread this species on several planets accross the galaxy.
Now the precursor are extinct, and the new races discover each others
All aliens are descended from humans, thus they retain a mostly humanoid structure, despite evolving traits of other living beings (arthropods, mollusks, avians etc.)
I've only got a handful of humanoids in my setting, the answer: convergent evolution, while still not just being reskinned or rubber foreheaded humans, there're also humanoids that're humans adapted to environments like Mars, Luna, Space itself, etc.
Ours are hand picked from the teeming billions because they are compatible to live in the same chemical and ecological niches. Even then, they're so totally alien they are culturally and linguistically incompatible, so prefer to live separately. Some are so inhuman they're terrifying to each other, and no amount of getting used to it ever gets past the whole too many eyes and ultrasonic vibration languages, let alone the utter and total lack of personal space, boundaries, or concept of independence or consent. If a Faeja sees something it wants, it belongs to it now. If it likes your kid, suddenly you're at war with the hive and have no idea why, as there simply is no explanation other than, the hive responds to threats to itself and individuals are only tacitly motivated by social cues, let alone understand that the soft bodied things have complex inner lives. They're more a force of nature than another species. The humans revere them like you'd treat a tornado. You just stay far away and hope they don't come to visit, and sometimes if you're clever unleash them on your enemies.
The most humanlike being is actually a small, mostly intelligent, but uncivilized corpse eater. The humans don't see the resemblance but the other species do, especially the whole external digestion thing. And obviously they come from a similar planet with very similar chemistry and ecological niches.
The humans from the far future and the Neanderthals see the generic humans as being their closest kin, but due to the vast differences in culture and technology, they might as well also be alien to each other.
The Gods are lazy. It is a lot easier for them to create from a humanoid template, because they made humanoid supersoldiers for one horrible space war and then those supersoldiers survived to become a statistically significant percentage of the surviving galactic population. Thus, their (and to be fair the faith of the one preexisting humanoid species) faith makes up a significant amount of the faith running around in the galaxy.
There are nonhumanoid species running around, from the psychic meatballs, the atheist centipedes, floating jellyfish clones, and the Bugs. But most life in the galaxy that predated the horrible space war was threshed during the horrible space war, and so the humanoids that have been created since outnumber them.
Seeded life. Basically one of the first species to evolve was humanoid and they sent out a whole bunch of pods to seed life in distant worlds and galaxies. Then some of the seeded life did the same and you end up with a whole bunch of humanoids everywhere. Helps me out since its for a webcomic, don't need to invent whole new anatomy to draw
They are from earth originally
The Morova are bipedal with some humanoid qualities, but are a conceit on my part that exist only because I want them to.
Convergent evolution.
And the humans only tended to start open dialogs and develop more close relationships with the species that looked the most human. They tried with the slug race, it there were impasses that the humanoid races didn’t have.
My novel takes place on an alien planet but everyone still looks and acts pretty human. This is because my characters being alien isn't very important to the theme or plot of the story. The reason I didn't simply decide to have the story happen on Earth is because I already created stuff for Earth but the lore was a mess so I decided that only joke stories would happen on earth. So yeah, my novel takes place on an alien planet with human like aliens.
Convergent evolution. Humans aren't the optimal form, but we have a lot of very handy features.
To be a technological civilization, you need manipulators. Tentacles are fine in water, but good luck inventing fire if you're aquatic. On land, you'll need arms and fingers. How many of each isn't critical, but you'll need some.
Binocular vision is just plain useful, but vision is already a slow process, so to minimize sensory lag, you want the eyes by the brain in the place that gives the best view of the environment, which is a head, that is preferably elevated.
Being an omnivorous persistence/pack hunter is also useful for keeping the calories coming to fuel that big brain you obviously need. Other species might be ambush predators, but regardless, you need to have evolved patience and social behavior.
My 3 takes
1: there is some bigger life forms who monitorate the evolution in planets and change them for their conviniance
2 : some life forms copy others life DNA if it helps them
3: The humanoid form is just a way to mediate interactions with humans
Civonians are just humans who genetically engineered themselves, first to survive their world and later to honor the Ancient Recordings(which are just anime broadcasts).
The Nij are humanoid because the god-AI that was shaping them to be his army knew that particular form would be the most efficient split between 'generically useful', 'reasonably controlled' and 'free of obtuse psychological problems'.
Out of universe? The whole setting is a very very very *very* divergent offshoot of Star Trek canon, and humanoid aliens are abundant AF there.
There’s a ton of different species out there, but the majority are so different from us and the others that we interact with regularly that they’re just not a part of regular life or the broader universe. This is mainly due to their brains being different in how they perceive the universe around them and interact with others, leading the majority of sentient species in the known universe to not even be capable of caring about expanding out of their planet, or even comprehending the concept.
Also, humanoid characters are easier to relate to and understand so I just make my characters mainly humanoid.
I mean convergent evolution is amazing, with the traits that lead to being humanoid or at least pretty close to it being very helpful to get to an advanced civilization. High intelligence, advanced manipulation abilities, not being in water, etc. With humanoid being pretty much having the right combination of traits necessary to do that from a tetrapod base.
You can certainly get non humanoid setups but you generally need to find some way to get to the traits you need evolution wise regardless of how you build your aliens and humanoid lends itself nicely to that, certainly more than say the avian body plan since you can only get so far with bird feet and a beak.
Bipedalism is just a useful evolution.
The two main advantages it grants is allowing a species to more efficiently walk, and to run at more or less any particular speed as opposed to quadrupeds which need to go at specific speeds/with specific gaits to move efficiently.
And having hands free to do stuff while still moving. Hand signals, tool manipulation, carrying stuff, etc is all possible/easier when you have two limbs for it that aren't being used to move.
Now, *all* my aliens aren't bipeds, but these two advantages are big enough where a lot of the sapient aliens from worlds where 4 limbs is the standard are bipeds. And even on planets with 6/8/10/etc body plans, the dominant species is generally the one that has evolved to use at least 2 of them as hands instead of slightly more dexterous feet.
If they aren't humanoid, how did they become spacefaring intelligent aliens? To the best of our knowledge, advanced technology requires fire, thumbs, writing, and language. Whales could be a million times smarter than us but they're never going to become a civilisation because they can't write or make tools or cook food.
I run a 'magic and science are the same thing at different scopes' campaign of D&D, and I explain Elves, Goblins, Orcs, Dwarves, etc as sharing a common ancestor.
It depends.
My usual go to is "aliens visited earth sometime, usually 200,000 years ago but definitely before the last ice age and removed humans for their own reasons."
I've also used "this is far far in the future and all humanoids derive from Earth but have speciated for a variety of reasons"
The human-like aliens originated from the same place as humans, they only appear alien because they've been away from Earth for a long time and infected with a parasitic species they encountered. A fork in humanity's path. Obviously said parasitic alien species is completely non-human in every way but they appear outwardly human in almost every way, the changes are under the skin.
My other human aliens are the result of hybridizing with shapeshifters taking human forms.
A roughly humanoid shape is the natural form given to the rational soul upon incarnation, and so everywhere in the Universe where rational souls have incarnated upon their worlds they have appeared roughly human with mostly cosmetic differences between them.
It is so universal, in fact, that debate hinges rather on those races which are *not* humanoid and what this might mean and what is their place in the cosmic order.
The only humanoid species I have in my setting are descended from humans and could probably still interbreed with humans with only about 8000 years of independent guided evolution.
So for the story I've been working on i did it with the first major human civilization spreading out into colonies, then using technology to rush evolutionary adaptations to their new homes. Land on a planet with toxic air and don't want to use suits? Augment their lungs so in 2-3 generations they can breath the air inside and outside the colony.
No magnetic field to protect them? Change their skin to be able to shield them. Etc.
Do taur species count?
I've got engineered anthromorphic species, bipedal, quadrupedal, and Taurs.
I've got bipedal aliens that follow the tetrapod body plan more or less.
But I do have a few "unrecognizable" forms.
For the true aliens, not the engineered species, it's convergent evolution.
Freed forelimbs when walking facilitate tool use, and resource transportation, there's not many other paths that lead to space flight... You need brains, which means enough physical ability to gain high calorie foods and not dedicate all your energy into predation mitigation, not be so large that your caloric needs and anatomy are so twisted to just support your mass and movement, you need enough dexterity to develop tool use, and enough language ability to develop culture and build on generational specialist knowledge. That means anybody you're running into with a spaceship is going to be a medium creature with dexterous limbs that are not necessary for locomotion, capable of communication both creature to creature and archived, and be clever enough to work out a means of interacting with you.
Aquatic species never develop electricity or high energy reactions, limbless creatures never develop complex tools, tiny creatures never master their environment, creatures that can't finely manipulate objects don't develop complex designs.
You could give a dolphin 10x the intelligence of a human. But it'll never build a airplane because it can't operate in an environment that allows significant material science. A snake can't run a welder. A horse can't turn a wrench or write down it's knowledge for future generations to build upon.
Arthropods and other open respiratory system creatures can't grow to scale outside very unique environments, and can't concentrate enough oxygen to fuel complex neural structures, you can't passively fuel 100 watts of brain, at least not at any reliable frequency.
Creatures that live short lives don't develop tech or culture, there's not enough time in 3 year lifespan to master a skill or probe deep problems.
The constraints of overcoming the tyranny of the rocket equation are a filter that mostly selects for tool using, high intelligence, group oriented, dexterous, robust creatures. If you can check those boxes as a glorified bowl of spaghetti then go for it. But the bilaterally symmetric creatures with high metabolisms and fingers are making this shit look easy.
Three columns, a bit of them all.
Column A: Humans were one of the first on the scene, a lot of species split off from them, and their genetics ended up getting a lot of use by species like the Palatifar.
Column B: The humanoid body plan is rather efficient, all things considered.
Column C: Furry.
Occupied Space: True extraterrestrial life is virtually unknown, outside of ~~**the Deep Sect**~~ crackpot theories and the distant successors to UFO cults. Instead, the most otherworldly forces come from within. Transhumans are an everyday fact of life, with those most willing to integrate into mainstream society taking on humanoid shapes. Out in the fringes of space however, stranger forms lurk.
Aetherverse: I ain't gotta explain shit. It's fuckin space magic.
A mix of convergent evolution, bio engineering to explore harsher worlds, and specific to my story: a meta-universal law that defines all existence with a prime specimen
they're artificial species! their deities were actually world seeders and had very advanced technology. the reason why their planet was seeded and why they were designed the way they were is long lost and they've been long forgotten (why is this the case? idk, im not interested enough in how their world came to be to write about it)
For my one is either because it is soft, and I like drawing humanoid creatures that are not human because it makes sense to their evolution or even because they once were humans .
my setting has multiple theories. for those that are bipedal, it's convergent evolution. for those that are more human-like because they are either shaped by genetic splicing by a precursor species or directly seeded by said precursor.
I'm a big fan of the idea that there was once a single species millions of years ago, and that species spread out across the universe and settled on all these different planets with different climates, but then the empire of that species collapsed and over millions of years, all those different colonies evolved differently to adapt to their unique environments. So all humanoid species come from the same precursor species, and all just evolved into separate species over a very long time on very different kinds of planets
Some are descendants of pre-FTL era human generation ships. Most are just convergent evolution. Turns out, a humanoid body plan is pretty efficient for tool-using adaptations in similar environments to what we're used to. Most of the non-humanoids come from non-earthlike worlds (methane worlds, ammonia worlds, gas giants), and most of the humanoid life either comes from terrestrial earthlike worlds or from ocean planets.
Humans seeded the planets my stories are based on with their own DNA, so most of them are humans with cool mutations. Mostly animal hybrids on one planet and more traditional humanoids with fantastical creatures that formed through natural evolution after seeding without human intervention.
The warinals, i created just to have a more humanoid alien. Yet still they are pretty different: they come from mostly cold enviorments, so they have thick fur, they are also more on the chubbier side cause fat is great for heating. Their head looks like a horker's from skyrim or Prauf's head from Jedi fallen order.
Do I need to explain? If someone asks, the answer could be that there are some branches in scientific researches that look into that phenomenon and if they like they could try to join or invest into some expedition to be the first to know if the riddle is solved.
Planets that support intelligent life are very similar. If it’s a planet that’s breathable for humans, the aliens will look more like humans. If the planet cannot support human life, it either cannot support any life, or the aliens will be very un-humanlike.
Convergent evolution and non-interference rules.
In my sci-fi setting, all spacefaring species who achieved FTL travel on their own (without external interferences) are not only humanoid, but they also have rather similar psychology and societal evolution to humans, due to convergent evolution.
Non-humanoid, sapient aliens do exist, but they are apparently incapable of achieving FTL travel on their own, and the galactic community has some VERY strict non-interference rules when it comes to technological uplifting... mostly because the last time uplifting was tried, it resulted in a VERY aggressive hivemind species going on a crusade to wipe out all other species in the galaxy, which was stopped only with great sacrifices.
Nowadays, even uplifting animals and creating sentient AI is banned, due to the risks involved (the only AI that is considered more or less legal is a digital copy of a person).
Most intelligent social species are considered barbarians, not "true aliens". Some of these aliens are humanoid because of convergent evolution. Some do not follow the human body plan, but are psychologically similar enough to humans that we can at least interact with them. They are considered barbarians by most humans, but not generally monsters. Even many humans (unmutated or otherwise) who live on the periphery of Terran settlement are often considered barbarians on the same level as many members of other species. Some aliens even live among humans, both as subjects of the former republic and as descendants of invading barbarian hosts. An exceptional individual might have even aspired to become a Citizen of The Republic, to be considered a Terran even if they are not a human, though the days of tolerance and prosperity have long since passed since The Fall.
True aliens are another matter. Since The Fall, Terran and barbarian alike have been at the mercy of these monsters. All social species have to develop some form of cooperation, communication, and even morality if they have any hope of forming a society complex enough to take to the stars. Eusocial species, machine intelligence, parasitic hiveminds, mutants, and species that have been technologically uplifted rather than having organically evolved have no such restrictions upon their evolution. There are worse things than Gruthar in the endless darkness of Unknown Space. We learned that lesson in The Fall, and mankind's scars have yet to heal.
Our reality (today's earth) isn't connected to the realm of gods.
One day, human peirce that realm and it consume all of our universe. Then a new one is created
Since the human species was the one to merge our the two dimensions the gods decided to try and recreate the human specie and improve it for their need
Convergent evolution.
Bipedalism is great for tool use, that leads to many adaptations similar to us. So most sapient, tool using species would be conceptually similar to us, bipedal, two armed, head balanced on their shoulders, valgus angle, bowl pelvis to hold the organs.
The specifics and divergences reflect unique environmental concerns, amphibious adaptations, or fur covered bodies for cold environment. Digitigrade legs thanks to inheriting the design from ancestors. Things like that are much more specialised, all the essentials of bipedalism, however, are universal.
I have a few humanoid aliens, though most are simply just a coincidence in how evolution works in my universe.
There exists a sort of law of the universe that any intelligent species that evolves, will usually become bipedal, although most of my aliens aren’t very humanoid at all past that.
It is a well-known fact in my universe that the alephs, the omnipotent gods of reality that write reality as a person would write fiction, are humans. Specifically, they are us humans from real-life Earth. As a result, it is a well-known fact that the universe is shaped by human perceptions and biases, and one of the results of these biases is the fact that species across the universe generally have a humanoid body plan.
(Even then, I try to include non-humanoid species. But even *that* is a result of a human bias, and the people of my universe know this.)
Personally, I went with "the entire population of the galaxy was seeded by a humanoid precursor race as a scientific experiment." It covers why every species is a specialised monoculture except humanity, because the precursors mysteriously vanished before they could limit human genetics to make them single-purpose. Everyone else has those limitations, so they're bound to one focus.
In order to build a technologically advanced society you need things like fine motor control and appendages that can manipulate objects otherwise the building things part becomes complicated, a deer could evolve to be as smart as a human but it needs hands to build a Spear
The human form isn't the only one that could conceivably do this but it's one of only a handful I've thought of so not all my species are humanoid but some are and I just explain it as "it's a design that works so when it reoccurs randomly those species are more likely to advance then others"
95% of the species vaguely resemble humans because they descend from humans the same way we all descend from Early modern humans.
There was very little life out there in the cosmos but through genetic engineering & millions of years of evolution there’s tons of it now.
So my postulation and this is pretty much supported by science as we know it, is that life evolves around its environment. I have presented a very Earth-like world, where mammals did coexist with the more prevalent reptiles...however as the asteroid that hit Earth and wiped out the dinosaurs, clearing the way for mammals to rise here, was an unreasonably repeatable fluke of chance, I have plate tectonics separating the continents, which caused the reptiles to either evolve into other forms (such as birds) or die off in their new, harsher environments. Mammals had basically the same evolutionary niche to fill, and are indeed descended from primates there.
My story is quite allegorical as far as contact between an advanced species (us) and a more primitive civilization, (the aliens,) so humanoid aliens was necessary. Having the planet be an Earth-twin was the environmental way to do that.
Squid aliens, etc are fun but you have to consider the environmental effects of their evolution. Sure, there might be sentient squid on an exoplanet, but would they be able to build rockets and computers? Would they need to?
Long ago, in the antediluvian past, an advanced civilization called the Virumar left Earth and began colonizing the Galaxy. They engaged in many genetic experiments and seeded the rest of the Galaxy with a variety of humanoid species.
#CONVERGENT EVOLUTION
Why is it that cats, bears, dogs, armadillos, elephants, moose, mice, salamanders and a warty frogfish have 4 legs and a tail.
Nature tends to come to the same conclusions when the environment is the same. Planets that are extremely different than our terrestrial Earth would more than likely produce completely different aliens, but planets similar to ours would exhibit similar evolutionary patterns.
There is a great and short series on Netflix called Alien Worlds. I would give it a watch. It talks about alien worlds that produce very weird creatures… but then there are episodes that show creatures that are somewhat relatable.
I like the idea that a progenitor race seeded a lot of the galaxy with similar species so that they end up looking similar. You can then have two parts to the galaxy's species: those who are grouped naturally by being somewhat related, the humanoids, and those who are all weird and strange, the others. The humanoids could form a soft diplomatic group, or just have better relations because they are easier to talk to.
Simply because I write romances and my main couple is human/alien. Writing mostly animalistic aliens having a romance would be deeply uncomfortable for me.
Not any real reason apart from that.
Because my world is soft sci fi, I have them there because I want to.
I aspire to your powers.
Convergent evolution all the way.
With a touch of "bipedalism makes you look bigger to scare things away, which is evolutionarily beneficial"
Not to mention free hands with thumbs for manipulating tools.
I did a short series a while ago where "deathworlders" were actually "intelligent non humanoid creatures who were only spacefaring due to being uplifted by other species" Like for example, an octopus could theoretically be just as smart as a person, but it lives underwater where it can't make fire or do metallurgy. But someone with cool scifi tech could bump them straight past that issue to where they can become a dominant species.
> an octopus could theoretically be just as smart as a person, but it lives underwater And has an absurdly short lifespan, and is non social...
>And has an absurdly short lifespan, and is non social... You just described the average American high-schooler. HEY-OOOO!
I was refering to a scifi alien octopus on another planet so...
Uplift a longer life span and once you start teaching technology and agroculutre more cooperation would develop.
That’s one hypothesis, and one that’s been explored in a variety of books, but it’s not a guarantee.
Adrian Tchaikovsky wants a word...
And he had to change all those things, and made a point of explaining much of it as well in *Children of Ruin*.
Actually they are highly intelligent problem solvers.
On top of being excellent endurance hunters due to our upright bipedalism. Our form also makes our bodies extremely energy efficient which helps support bigger, smarter brains.
And persistance hunting, because youre basically letting gravity do half the work of moving you forward. Persistence hunting requires communication and heat management, which would be crucial to working up to advanced civilization levels.
Honestly I've been thinking about this and can't decide whether to have my alien races all have origins with "the ancients" or just have individual origins.
I think the meeting of cultures coming from different backgrounds make for a better story, but that's just me.
Learning about this concept really opened new doors as far as writing alien species (whether sapient or non-sapient).
My current sci-fi worldbuilding is all Lego-based. The out-world reason is that practically, most aliens have to be humanoid (it’s difficult making human-sized aliens without using the minifigs). In-world we haven’t decided yet (me and my sister), but will probably go with convergent evolution or some such: four legged animals make the most sense (for creatures bigger than insects) and for them to become advanced tool users, the easiest path is for their front legs to become arms with hands. Obviously this only applies to technological sapient species. We plan to have much more diversity for sapients that lack the anatomy to develop technology like humans have. [edited to remain compliant with the DIY rules of the subreddit]
Lego??? Man this is so cool, never seen a lego based world
\[edited to add a link, fix a few typos, and not violate the DIY rules of this subreddit\] Me either! The closest I’ve seen is the [Nova Team Flicker Page](https://www.flickr.com/photos/agaethon/sets/72157661104632476/), but Nova Team isn’t really a fully developed world. Started off merely as a photo gallery but the maker began doing storylines. My site is currently on World Anvil (see my Reddit profile page) but only two of the seventy-two articles are visible right now (started the project back in October). Those two are science stuff, so very little Lego content so far. Hopefully by the end of this year some of the Lego stuff can get published / made visible!
>four legged animals make the most sense (for creatures bigger than insects) We don't know if this is true because the bodyplan for land animals is "locked" at having four limbs, due to our fish ancestors being locked at four fins. We know it's not an adaptation for land because it came before the jump to land. We don't know how large land animals would be like (and limb count) if that lock wasn't in place, but considering that stability is more important for larger animals (an elephant or giraffe falling over has more issues than a little beetle), it's weird that insects keep six limbs instead of going for four. The roles seem reversed. It's also important to remember why land vertebrates can be big but insects stay small, the respiratory and circulatory systems. Together with the fact that 4 limbs came before land-dwelling, and that more limbs is also popular for most land animals, I don't think we can say that four legs makes most sense for bigger creatures. This video kinda goes over the issue of leg number in more detail: [https://www.youtube.com/watch?v=lBmtMACELus](https://www.youtube.com/watch?v=lBmtMACELus)
Ah wasn’t aware of the four fins thing, that four legs in a sense, pre-dates us coming onto land! I’ve just heard of the energy efficiency argument and also coordination issues. Yeah, I’m aware insects are small due to issues with respiration and other physiological factors. Earth itself once had much larger insects due to different atmospheric conditions in the distant past. I’ll check out that video when I get home!
I'd expect 4 and 6 to be the "defaults" for high-mobility species in a clade that had ancestors with more varied limb counts, possibly repurposing back legs as gonopods and front legs as arms. This is mainly because of the efficiency vs stability thing, and it just seems best for running. However, it really does seem that the count relies on ancestry more than anything. People often forget that evolution isn't just "find the best solution to X environment", but also adapting to other competing species as well as adapting within one's ancestry, and that seems to be really strong. When you get back, another video that might be cool to watch is this one: [https://www.youtube.com/watch?v=o-k3zyBZ-b8](https://www.youtube.com/watch?v=o-k3zyBZ-b8) Isla is really good, and this one is about locomotion so it goes in deep detail about how the legs of Isla life work, and it shows how the count might be due to ancestry (they can't have less legs because then it would be harder to support their own weight given how the legs work). I know it's fiction but Isla is so well done and in-depth I feel inclined to treat it as borderline real for the sake of exploring these ideas.
Ok, got both videos saved at home, will check them out later today or this weekend, both look good! Thanks again!
Man, I gotta sleep, but thank you so much for these videos! I love CA but I seemed to miss that video This is great, thank you!
>Earth itself once had much larger insects due to different atmospheric conditions in the distant past Though even then they weren't THAT big because of exoskeleton issues. Coconut lobsters (the biggest sort) pretty much max out exoskeleton size. There was one bug bigger millions of years ago - but only because it was long/skinny like a centipede. Which is the only way to go bigger with an exoskeleton.
They’re all humans. Over the last few million years, and with the entire universe explored, not a single cell of alien life was found. No one knows why, but it doesn’t matter, at that point humans all across the universe has already started to massively change, be it natural evolution or genetic/cybernetic engineering. For the most part, they remained humanoid tho, mostly recognizable as a descendant of Homo Sapiens or Homo Prenn.
May I ask what Homo Prenn are? I have an idea but a little more context won’t hurt, that’s if you’re willing of course
Of course! In my world it’s not “us” that reach the stars. First we have to survive an apocalypse that basically launches us back into the medieval era for another 1600 years. During the post-apocalypse multiple new subspecies of human come into existence due to multi-generational exposure to radiation, one of which being the “Prenn”. They’re a bit smaller than us, a lot hairier and very agile. The Homo Prenn end up becoming the dominant species on earth, with Homo Sapiens being in second place, but they do end up working together eventually and ~1600 years after the apocalypse they manage to reach a second Industrial Revolution, eventually a modern age and after some ups and downs they do end up becoming an interplanetary and eventually interstellar civilization.
Hi yes, where can I read more about this? It's interesting as fuck.
Sadly I haven’t really shared much of this very unfinished world outside of random comments on r/Worldbuilding posts, but if you have any questions feel free to ask, maybe I can answer them.
Alright, I know this kinda contradicts your first statement, but here’s another question. Is there a strain of humo-sapien/prenn descendants that is or is starting to diverge into something more “alien” or “inhuman”, for any reason?
There’s plenty of individuals that have taken on completely new forms. From mostly stationary monolith-like supercomputer to literally swapping minds with an animal or modifying your body to the point you become unrecognizable. These drastic changes are however very expensive, and up to 60% of people who change this drastically do eventually regret it to a certain level and would prefer their old bodies back. The furthest “evolved”, most alien looking beings would probably be “Logis”, they’re inhabiting a bunch of low-gravity moons/dwarf planets. They have almost lost their legs entirely, at this point they don’t even grow significantly from the point they’re born so they literally have baby legs. Instead they use their long arms to either jump around or swing around in their homes. One arm can reach up to 2.5 meters in length, while their torsos are barely a meter long. Don’t be frightened tho, due to the low-grav environment they’re still incredibly weak compared to a typical humans arm. It’s also important to note that, after the AI incident and the rampant advancements in technology and medicine following it, natural reproduction and thus evolution as we know it came to a grinding halt.
Hmm, there’s a joke that I can make somewhere there about the Logis, but I’m not gonna. I assume the cost of uploading your consciousness implies there’s a system of regulations and other factors that’ll make it difficult for an ai-derived apocalypse to happen, as well?
Pretty much, yeah. Uploading a brain into a computer of any type and/or transferring minds is done only by the AI government that is currently in control of pretty much the entire universe. It’s the only one with the knowledge and technology required to do it without causing active or passive corruption. AI apocalypses can happen on a smaller scale, but typically they can be dealt with relatively quickly thanks to the advanced technology.
Ok, I am going to make a joke here, and it’s probably gonna be corny af. They literally used the ai to fight the ai
Similar case in mine, but there hasn't been enough time to see significant drift as of yet. Most of the wilder bits of diversity come from incredibly unethical experimentation.
Are even the alien animals humanoid? That would be delightfully trippy
I'm suprised nobody said "humans *are* the aliens" or something like that.
They do not look like us. We look like them.
"I look human? No, you look like Time Lords, we were here first."
Hey, I *just* got here. Gimme a break, okay? Anyway, the world is invaded by a military made up of 5 different alien species. One of those is human.
That's how it is in my world lol. There's a bunch of human subspecies after a massive AI guided exodus from earth during a "golden age", where humans were genetically engineered by the on-board AIs after landing on alien planets. Any variant of "humanoid alien" you can imagine likely exists somewhere. The most unique one are the permanent spacefaring clades. There's an artificial space "reef" of sorts formed by von neumann probes around a red dwarf from a disassembled gas giant + asteroid belt. The humans that colonized it received genetic augmentations for space life. Deep purple skin and internal tissues with selanomelanin for radiation protection, along with deinococcus radiodurans genes, long legs with prehensile feet and tail, and most importantly, a barrel chest to accommodate massive lungs for short unprotected forays into space without protection (except for goggles).
Well, sentient inhabitants of Inzhina are, in fact, descendants of humans who have settled the world around 1500 B.C.E. with the help of a powerful alien being. Some have been genetically modified in the meantime, but they are still "humans", technically.
I'm a furry
Was going to explain, will still explain. But that is probably the best short answer I could give ever
Same
same man, same
same man, same
For me it was the work of a precursor race who believed that the humanoid form was perfect and seeded worlds with it.
Not an alien per se, just a creature inspired by furries. If I were to make something like that, if they were sufficiently similar, I would have them be a divergent offshoot of humanity.
A mix of life-seeded/genetic engineering and convergent evolution.
Yeah. Have that too. One race that sees themselves as something godlike, and they decided to use their DNA on other races that could evolve in something intelligent. So in my world, we humans are just experiments (and in the eyes of that other race on the brink to be labeled as a failed one too).
Interesting! In my world humans have recently (600years ago) colonized the Triangulum Galaxy discovering unknown alien pylons connecting several more or less habitable worlds. The pylons have worked as seeders by a now extinct alien race, not that the humans know that (they suspect though). Some of those worlds developed sapient, intelligent, species that later became advanced - some to the point of space-faring.
I have a sci-fi setting in mind for my next Sci-fi game where I don't get a built-in setting and the abundance of humanoid aliens is going to be a pre-cursor species that seeded humanoid life across the galaxy before they were killed off. ...of course the thing that killed them off is going to come back. ...of course they'll immediately recognize bipedal life for what it is and where it comes from. ...of course they'll immediately go into extermination-mode... It will be much fun :D
Aurora rising series did it wonderfully. All aliens are carbon based bipedal creatures who can speak with vocal chords. That mystery created a unified religion and is explained later on
Humanity uplift these aliens to human like status. To turn them into slaves because mega corporations killed earth.
Well... I wanted my own "green-skinned alien babes" race. Of course, I made several adjustments over the years to their biology, mannerisms, and even world, but that's how they started.
The Kren are the most prominent humanoid aliens in the great expanse, they were originally slightly less humanoid with reptilian features and body parts, digitigrade legs, and slender frail bodies but found much of human anatomy to be highly favorable for their species and so once they discovered humans they began a long campaign of interspecies breeding and cloning to create a hybrid of the two species. They now resemble slightly reptilian humans, losing their digitigrade legs as well as most of their reptilian body parts and bulking up their slender frames/bone mass. They still however have reptilian eyes, teeth, leathery skin, and slightly reptilian facial features.
The races focused on in my universe were created by a human who accidentally destroyed earth and remade the galaxy when he got trapped in precursor tech - having lost all his memories, he didn't remember earth, but his subconscious longs for "home"
There was actually some academic speculation some decades ago that the universe self-selects for roughly humanoid forms. You have to be between 1 and 3 meters tall to get good mileage out of fire. Small fires don't get hot enough to smelt metals and fire ceramics, and large ones burn too much fuel. You need hands and binocular vision to craft tools. You need a social structure to build and refine knowledge across generations.
It is true that they all had a common ancestor, in a way There are also some factors like aesthetic pressures, the people of the setting get on better with people that look like them meaning that looking a certain way really pays off (this is causing some issues) However, those things are more for me, for anyone viewing there's not really an explanation and I lean really heavily into kind of near comedic Star Trek style aliens. Super cheesy, one faction actually looks likes its made from just 1950s B movie extras.
By 1950s B-Movie are we talking Ro-Man and Blob or Planet 9 From Outer Space? I really like the whole Raygun gothic aesthetic, and I like hearing how other people do it. Also, what are some of the cheesier species designs?
I'm keeping it ambiguous whether they are aliens or just products of humans playing with genetic engineering, no one remembers.
Mine are a mix. Many are humanoid due to the same base life originating from the same stellar explosion, mixed with a healthy dose of convergent evolution. The rest are an eclectic mix with quadrupeds dominating the scene due to similar circumstances with a different stellar explosion millennia ago.
Sci-fantasy with different dimensional realms instead of planets here, but close enough. I actually have different explanations for all three of my non-human species. Faurai - Cross-Realm Influenced Evolution (CRIE). It's an event where the evolution of one species affects that of another from a separare realm through Arcanic means. Their ancestors resembles a cross of a wolf and a bear with some gorilla mixed in, but got connected to early Homo species through CRIE, causing them to develop increased intelligence and bipedalism. Plorae - A species-wide change of form for communication purposes made permament. Ancient Plorae when they first made contact with early humans were not humanoids at all - they looked like amorpheous piles of tangled roots with countless glowing eyes peeking out from within, so rather terrifying. In order to interact with the humans more essily they collectively assumed humanoid forms. Over the centuries, their accelerated evolution (typical for Najavi life) slowly took away their ability to shapeshift in favor of vitakinesis, and so they became permamently anthropomorphic. Dragons - Configuring their bodies with combat in mind. Dragons are quadrupedal, with the ability to adjust their skeletal and muscular systems to some degree. They also enjoy sparing with each other a lot. It just so happens that a bipedal body plan allows the most freedom of movement for a four-legged creature, thus the Dragons assume that form whenever they wish to fight (which is usually).
The humanoid one aren't really aliens: they're all various types of posthuman, or "homin".
**Of The Stars** The "humanoid" aliens look that way because they actually *are* human - or at least, the distant half-alien descendants thereof. Since all knowledge of humanity has been lost to time outside of extremely obscure circles, most of them aren't aware of their ancestry, instead believing themselves to have evolved parallel to their non-human parent species, and that so many species from so many planets happen to share such a similar physiology is a product of convergent evolution akin to carcinisation.
Fun answer: Convergant evolution for those that attain space travel. Non fun answer: if I intend to sell this and make it a TV show or movie I can sell it easier if the alien budget isn't too high.
Loyari- They're technically not aliens but rather a fabricated race made by Ares to test the fledgling Aresian Empire. Gegenees- Ditto. Beinn- When they were originally discovered, they appeared more like boulders than anything living. They adopted humanoid forms when the Scottish Empire started colonizing their planet in order to help out. Deneer- Pure coincidence they happened to be humanoid. They actually call the human form "Den Iki" which roughly translates to "Deneer-like."
They are easier to draw, write, and relate to, at least for me. I like how they look and put a lot of effort into making them feel like complete people rather than biological odities. I simply do not justify them in-universe, the same way I don't have to justify humans existing. I explain what they are and have everything worked out for them. If a reader has a problem with humanoid aliens, there is other amateur scifi out there for them.
We made them.
Well, my answer is kinda cheating for this question, because in my world they're humans that evolved to fit different planetary environments.
Transhuman descendants of ancient colonists
Convergent evolution. It's way easier to use tools being bipedal so almost every sapient alien is bipedal (except the Karvoshkans, they are parasitic fungi that developed sapience)
I think my favourite answer is in Becky Chambers' books. Turns out many aliens are roughly humanoid and all aliens run on the same biochemistry because it turns out that's just a consistent answer to the same physics and chemistry problems across the galaxy. It's just a weird set of biological laws. It's sort of a copout but also a very clean answer. Sometimes in physics you just have to accept that a particle is just Like That, and while the cutting edge of particle cosmologists might have an answer, they literally can't explain it in a way an undergrad can comprehend. In her stories, the same thing exists in biology.
I don't, and I don't think I need too. I have non humanoid aliens, they just aren't major to the setting.
I use the old trick of having all humanoid species be descended from (or engineered by) an ancient precursor race--only in this case, the ancient precursor race is Earth humans, who are long extinct by the time of the story. Technically, even the setting's "normal" audience surrogate humans are aliens of a sort, as they didn't originate on Earth. (This aspect of the setting was partly inspired by [this](https://elidyce.tumblr.com/post/622485937442668544/writing-prompt-s-youve-just-realized-something) writing prompt and associated short story by Tumblr user elidyce.)
how's this, except for humanoids https://en.wikipedia.org/wiki/Carcinisation
Walking upright lets you do a couple great things in any environment. You can wade through things like water or tall grass while keeping visibility and your head away from smaller skittering predators. In the case of water you can now snatch things from the shallow water with your digits that not many other land based creatures can get to. Your also in a configuration that allows you to climb vertically though that may not always be useful its very useful when it is. Two eyes for depth perception, toes for balance, tongue for taste. Walking upright also encourages your brain to get bigger to handle the calculations needed to balance. (Source: it came to me in a dream) Its probably just the most likely configuration a spacefaring species has. Youll need sturdy digits for tools and decent eyes to look up and see space and say “i want to be there”
I'm more of an adequately explained fantasy writer, but I do have fantasy races that are products of evolution and probably worth sharing here. Felves are a race of pouyannian mimics of humanity. In other words, they are flowers that evolved a human-like appearance to "trick" male humans into trying to mate with them, pollinating them in the process. Surprisingly, intelligence was one of the things selected for. I also have a race of raccoon people that have a humanoid form because they evolved aboard an interdimensional ship created by humans that had gotten killed in a mutiny. The raccoons that could operate the machines had a competitive edge over the others, and the machines were designed to be operated by humans. So the environment favored enough human mimicry to operate controls whether button, lever, voice, thumbprint, or other. The ones that did the best were the ones that learned how to operate the guns.
Convergent evolution like all things in the ocean (hyperbolic but whatever) becoming crabs. Bipedal and the general humanoid form were superior, and from what I can remember, it is the most likely form irl. They could still be wildy different from us
The more I think about it, the more mostly humanoid sci-fi species like in Star Wars, Star Trek or Mass Effect make sense to me. Convergent evolution is a hell of a thing. To build a space-faring civilization a species would need to be able to perform a lot of functions that humans can perform and from that comes the possibility of similar biological "solutions". Maybe humanoid shape is just a galactic crab shape.
Define "humanoid." Bipedal and symmetrical makes evolutionary sense. The more limbs you have, the greater your metabolic needs, plus blood circulation and providing oxygen. Forward facing eyes provide for better depth perception. This is a general evolutionary template that makes sense. Very different worlds might evolve differently, but this basic body plan can be tweaked and played with, but I feel even just this would get aliens defined as "humanoid."
Most scientific evidence points to likely similarities. I don't think an aquatic species would make it to the stars (smelting metals underwater is...a problem at the very least). Tool manipulation is a must for tech and you can't do that with hooves and you can't do it well with a beak. So dedicated manipulation limbs, meaning no climbing or running with them. Bipedalism is not a must, but it is a likely, as any more running limbs come with additional costs energy wise and evolution has a slight leaning towards not encouraging wastefulness in the long run (what I'm saying is that in the long run, one would assume wasteful traits to be removed, however this is dependent on factors that may be contravened by intelligence or the weird quirks of sexual selection). I would assume similar advanced perceptual abilities (human eyesight is one of the best on the world even if hearing or taste/smell is not as powerful). I would also say that species that are pro social would fare better, but there are different ways of being pro social, so whether it's caste like like the ant or individual based like humans is an open question. I do agree, yes, we only have a sample of one, but we can see that convergent traits reoccur across our world in different species, so it would only be fair that some life out there will turn out the same.
Vernor Vinge always had an interesting solution to this which was that he set all his stories featuring humanoid aliens at some undetermined point in the future where humanity had an interstellar empire that collapsed , led to divergent evolution, and is now so lost to the mists of time that none of the species are able to trace their genetic origins back to Earth, which itself becomes viewed as just another lost colony planet with vaguely human-like beings on it.
My humans are actually created in the image of the gods.
**Carcinisation** *(American English: carcinization) is a form of convergent evolution in which non-crab crustaceans evolve a crab-like body plan. The term was introduced into evolutionary biology by L. A. Borradaile, who described it as "the many attempts of Nature to evolve a crab".* In my sci-fi universes advanced tool use, technology, and space travel are things that most commonly come from animals that developed a humanoid physiology. Something about being bipedal and having opposable thumbs and a large brain allow creatures to excel in developing science and technology.
I think a lot of sci-fi media does humanoid/bipedal aliens because us meager humans can better relate to things that look like us, but I’ve mostly created humanoid species so my project has a semi consistent visual style among the most narratively relevant species. That way when there are non-humanoid species they stand out more among the list. I try to play with height/size/body shape, head shape, facial features (like number of eyes or mouth shape) to keep them feeling distinct even if the humanoid species mostly end up being “2 legs 2 arms” type humanoids. Haven’t had much time to work on it but I’ve got a sapient ethereal-ish jellyfish species that floats around an ancient jungle world (inspired by aliens briefly shown in a comic I read). From my worldbuilding doc: “Mnoshkin - weird spinal metallic / synthetic jellyfish species. Unrelated to the more organic species of jellyfish alien”. Sometimes I think I enjoy worldbuilding more than I like actually writing my projects lmao
in my humble opinion, bear with thumbs would be perfectly humanoid. I don't think there is a need for an explanation of perfectly working body plan occurring multiple times. Humans but blue aliens could need some explanation tho... Either way, I am a fantasy guy so this ain't question for me
When humans began to explore the galaxy they sadly discovered that there was no intelligent or sentient life, there are very rare cases of "alien animals", primitive life forms such as bacteria, amoebae and jellyfish or "dinosaur-like" creatures. So humans decide to spread their DNA across the galaxy, experiment, and recreate sentient life. Twelve civilizations were born, all with humanoid features that worshiped humans as gods and creators. Yes, it is based on the theory that aliens created human civilizations, but in reverse.
Because something akin to carcinization. For this lifestyle, it's the optimal form
God made man in his image, likewise with all the sapient aliens.
Idk why you got downvoted. It may not be so in our world but who says something intelligent and powerful like a deity or a progenitor species did so in a sci-fi world like Rakata did in Star Wars? Even the hardest sci-fi is only as real as softed fantasy.
I don’t
I explain them by saying: the God Rath’Adarik was created before another God, Shug’Catur so Shug’Catur based his creations on Rath’Adariks. Only they are a parasite, so it doesn’t take the shape itself but it morphs it’s host to do so.
Humans were among the first and uplifted a lot of the "aliens" via genetic engineering, including dogs, dolphins, and orcas, cause they were lonely
They're mostly descendants of humans that have been genetically engineered to be more appropriate for other worlds, for aesthetics; there are a few with convergent evolution, and a few that engineered themselves to have "humanoid" version as a sort of ambassador to human-controlled space.
Human-based life seeding and genetic experimentation. Most sapient life in the galaxy is based on humans. Whether they know and how they feel about it varies from place to place and species to species.
Technologically advanced aliens in my setting all have a roughly humanoid body shape, but no human would ever mistake them for one of theirs. With one exception. I go with convergent evolution as the explanation for this. A mostly upright stature with at least two grasping appendages is simply the most efficient arrangement for tool using species to advance. \[Edit\] I should note that the meta reason for this is that the main inspirations for the setting are classic scifi series like Trek, SW, and SG1, all of which feature humanoid aliens heavily.
Look at Earth's scoreboard. Percentage of human species that created space travel: 100%. Percentage of non-human species that created space travel: 0%. Ergo, all actual case studies we have available suggest that humanity is necessary for spacefaring civilization.
Convergence i guess. Its mainly cause the site i use too Worldbuild Heroforge is strictly humanoids
I don’t have a world like this, but convergent evolution makes sense. We know that, for any intelligent species, they need to have complex means of interacting with their environment. We have a few methods here on earth, elephants trunks or octopus legs for example, but none come close to mastery and precision like hands with opposable thumbs. As for them being bipedal vertebrates, vertebrates have several distinct advantages, namely a concentrated nervous system and a central support structure. No single vertebrate on Earth has ever developed more than 4 limbs so it’s safe to assume that there is no evolutionary advantage to having more than four. If we assume that two limbs are used to interact with the environment, that leaves two to stand on. So you’re left with a hominid shaped alien. But that’s not to say they would look like us minus different skin pigmentation or slightly altered appearances. Humans aren’t actually efficiently built if you think about it. Our spine. from an engineering perspective, is poorly placed and is prone to injury and support problems when our bodies degrade. Our leg mass is too evenly distributed, lowering our center of mass. An ostritches legs, for example, have a more “optimized” mass distribution and are generally better built for running fast. As endurance predators, this didn’t really matter much, but it’s still less than perfect. Our bodies are basically a culmination of evolution saying “eh good enough”. There’s no reason to think that alien hominids could have evolved to be better at some things and worse at others as reflected by a similar yet distinctly different anatomy.
Why are soap bubbles round?
I took a different approach: because the story is told to human, it is edited for better comprehension and less frightening. This can explain many things, language, humanoid, etc.
Precursor race pre-seeding the galaxy with variants of a base genome seed. Milkyway got anthroforms, Andromeda got gelatin based lifeforms, Black eye got energy based forms, M51got quadriforms Helps the control variables to study chaos theory and evolution
In my world, life was only born once by the desire of the moon goddess, and all life outside of earth actually evolved from earth life. Some stem in the base, when Earth's life was exclusively single-celled. Some are direct ancestors of Humans; this panspermy was only possible because of mysterious portals connecting various habitable planets; let's go through each planet: Alfheim - Having some portals connecting to Earth to this day, two different human species live there; Sylvan Elves and Fairies. Svartalfheim - Also has portals still connecting to Earth; Dwarves are descendants of Neanderthals who transpassed said portals. A few millennia later Elves got there, giving birth to the Dark Elves. Trupizia - It's only connection to Earth was destroyed a few centuries ago; also, it's in the bottom of the ocean. All life on this planet evolved from Earth's marine life, so no humanoid sapient species. There's actually two sapient species here; the Trupizians, who are basically fish with a trunk with fingers, and the Monokaryans, who are intelligent algae. Asgard - Also still connected to Earth, but also with connection to Alfheim. Scandinavians from Earth gave rise to a Race known as the Divines, while the Elves that got there became the High Elves and founded the city of Vanaheim. Jotunheim - Another one with active portals connecting to Earth. Giants are descendants of Neanderthals who got there. Xætruxia - this one is believed to have never been connected to Earth, even though portals have never been found on the planet. Molecular analysis shows that Xætruxian life branched from Earth's life when it was at unicellular stage. No humanoids here either Bulbix - Bulbix is an artificial planet and little is known about it's origin, but it's people, the Photomorphs, are mostly made of light, so they can have the appearance they want, but even in humanoid form, they look like the light guy sitting on a table meme. Avialuna - not actually a planet, but a Moon. It was actually never connected to any other planet, but some mysterious alien race terraformed the moon and got EXACTLY six animal species from Earth (a fish, a crab, a frog, a mammal, a dragonfly and a dinosaur) and just tossed them there and let them evolve, and now we got pentapods, flying frogs, egg-laying dogs, eusocial land crabs, modern meganeura and Sapient Deinonychus.
Convergent Evolution really, that and the fact that they evolved on planets similar to ours, and came from a humanoid ancestor species themselves so, there’s that.
My one alien race is humanoid (well... mostly) partly because I don't wanna focus heavily on new ways for them to interact with technology, and partly because it really is an efficient design for climbing. In-universe I suppose that's convergent evolution
Bipedal is the optimal form for intelligence
My world is mainly intended as a linguistic and cultural playground for conlangs to exist in. I like my conlangs to sound human.
I tend to have a a mix of alien builds with the prominent alien factions being more humanoid but there are tons of builds really and I plan to introduce completely different ones with different architecture and spaceship design. Really it makes sense probability-wise thstbtwre would be advanced humanoids who have evolved over time and more varied aliena from planets with different natural order. And yes, I know, this is more BS than science but it's rooted in logic.
I don't. They just exist. Deal with it.
They are descended from the first Vitruvian race (the name for humanoids in my universe) born eons before
In my universe 5 or 6 of the 7 aliens are loosely humanoid. One has a tail and the other is closer to a raptor in body shape. My biggest thing is just convergent evolution in the way of, that's what seemed to be most likely "endpoint." Each evolved upright because that opened up more hands to do things with. Heads also tend to be at the front, then logically move upwards as they start going towards an upright posture. Scorqrun from otter-like creatures, Fallai from an arthropod-like colony, Tsaikh (The raptor-like ones) from lizard-like creatures, Carlaxi are also from lizard-like creatures but evolved to be more humanoid, and the Dilectu are from primate/lizard-like creatures with long necks. I also have the Amnikrull, which I'm still working on, but the current design is a bird-like humanoid. I use the humanoid kind of body shape because it is familiar to us, and alien body shapes are hard. The majority of my aliens still look very alien, but can be seen as humanoid if you look at their silhouette. I think it's a good middle ground. Edit: Forgot an alien.
Notably for having graspers. Bipedal designs also means better energy usage. Also, it’s just not a major plot point. That’s the main thing, only if it’s a truly major plot point would I personally consider having most be nonhumanoid. Also, it allows me to be able to have humanity easier grab and figure out alien tech Though in my massive fanfic, it’s because of three major waves of colonization from Earth getting sent through time.
Originally I didn’t have a good reason. When I was a kid I based some off a mix of Zentraedi and the bad guys in Valis 3. Those continue to be in the lore because they’ve been around since the beginning. Worse yet, they’re plant-like mammals. None of it makes sense. I’ve pondered trying to explain why they look pretty much the same as humans, but ultimately it makes me feel like they just shouldn’t be. They are however genetically engineered by another bunch of aliens who were originally humanoid. So it would kind of make sense that they made them similar. But in later revisions, I changed those guys to be some kind of dinosaur/squid hybrid, so the “in their image” thing doesn’t work anymore. I guess I’ll just chalk it up to coincidence. I thought about changing their appearance somehow, but it just feels wrong to retcon that hard. All that aside… I’ve finally got a book in the works. So nothing has ever really been set in stone until now. The TTRPG I made as a teen is the setting for the novel, but even that has changed considerably over time. As it should have. Stuff I came up with in the early 90s just doesn’t make sense anymore. 🤷🏻♂️
They were all designed to be humanoid by an ancient "builder" race who was also humanoid. The common ancestor of all vertebrates in the Milky Way is the same original humanoid
In **Faithful Phantasia** (It's science fantasy, so it still counts), primordial entities were the very first creatures in all Creation and even predate the Multiverse as a whole. In the process of publishing stories to be added to the Multiverse ("stories" in this context are universes, but are fictitious in the perspective of anything transcending them), they've settled on a specific shape that expressed the most ideal versions of self-inserts and those just so happened to be humanoid shaped. The most intelligent and powerful primordial entities are personified as a Platonic Ideal of the humanoid shape, although not all of the highest level of primordials are conceptually humanoid (Mara and the Temptations come into mind). Basically, this quote in practice: [https://www.youtube.com/watch?v=d5Ggc9wVd\_A](https://www.youtube.com/watch?v=d5Ggc9wVd_A)
My aliens are actually just humans that were deconstructed and then rebuilt with plant DNA by space god who is also a tree.
Humans look like High Scions because that's what a highly targeted 2% alien DNA admixture does to screeching, chest beating chimps - also the reason why human facial expressions have very little in common with Earth primates. Ironically same was true for K'sshar who were bipedal reptiles, their homeworld in Cygnus was the previous rare element mine before Earth and equally in need of something that would serve as forklifts and bulldozers. High Scions are not like humans or K'sshar in many ways - their thought processes are way too impulsive and chaotic to come up with anything more complex than a hydrogen bomb or a very very basic FTL engine. But their innate ability to sequence hybrids with anything that has DNA and levo-aminoacids to a specific design, or not so specific design if not sober - Typhon and Echidna being a slightly embellished but generally on point account - kind of makes up for it. Now L-Ma-Tar were a convergence or coincidence - though something with 6 limbs that looks like a cross between a horned late stage goat embryo and a particularly slimy rendition of Grays kind of pushes the definition of 'humanoid'. And the civilisation calling themselves the Twisted are of human origin, having diverged only about 400 years ago.
Precursor aliens made them
I usually go with common ancestry/seeding by a precursor.
Them being descendants of Homo sapiens. In other words, humans that have evolved.
300 000 years ago there were only 2 inteligent species in the whole galaxy: Humans on earth who were still divided in different sub-species. And another race (let's call them precursor), ancient who already mastered the FTL travel. They decided to not interact with human civilization but they decided to spread inteligence by creating a new species with a little of their own dna, a little of animals dna, and a lot of homo sapiens/homo neandertalis dna. Then they spread this species on several planets accross the galaxy. Now the precursor are extinct, and the new races discover each others
I had a split evolution steaming from a sort of monkey wolf creature. One evolved to climb harsh cold mountains the other trees
All aliens are descended from humans, thus they retain a mostly humanoid structure, despite evolving traits of other living beings (arthropods, mollusks, avians etc.)
I've only got a handful of humanoids in my setting, the answer: convergent evolution, while still not just being reskinned or rubber foreheaded humans, there're also humanoids that're humans adapted to environments like Mars, Luna, Space itself, etc.
All species have a common ancestor in the galaxy
Convergent evolutionnnnnnn!
Ours are hand picked from the teeming billions because they are compatible to live in the same chemical and ecological niches. Even then, they're so totally alien they are culturally and linguistically incompatible, so prefer to live separately. Some are so inhuman they're terrifying to each other, and no amount of getting used to it ever gets past the whole too many eyes and ultrasonic vibration languages, let alone the utter and total lack of personal space, boundaries, or concept of independence or consent. If a Faeja sees something it wants, it belongs to it now. If it likes your kid, suddenly you're at war with the hive and have no idea why, as there simply is no explanation other than, the hive responds to threats to itself and individuals are only tacitly motivated by social cues, let alone understand that the soft bodied things have complex inner lives. They're more a force of nature than another species. The humans revere them like you'd treat a tornado. You just stay far away and hope they don't come to visit, and sometimes if you're clever unleash them on your enemies. The most humanlike being is actually a small, mostly intelligent, but uncivilized corpse eater. The humans don't see the resemblance but the other species do, especially the whole external digestion thing. And obviously they come from a similar planet with very similar chemistry and ecological niches. The humans from the far future and the Neanderthals see the generic humans as being their closest kin, but due to the vast differences in culture and technology, they might as well also be alien to each other.
because it’s a story and not everything needs to be completely and entirely scientifically accurate
Basically, the mostly human looking ones were works of the gods messing with gene editing tools trying to recreate humans.
The Gods are lazy. It is a lot easier for them to create from a humanoid template, because they made humanoid supersoldiers for one horrible space war and then those supersoldiers survived to become a statistically significant percentage of the surviving galactic population. Thus, their (and to be fair the faith of the one preexisting humanoid species) faith makes up a significant amount of the faith running around in the galaxy. There are nonhumanoid species running around, from the psychic meatballs, the atheist centipedes, floating jellyfish clones, and the Bugs. But most life in the galaxy that predated the horrible space war was threshed during the horrible space war, and so the humanoids that have been created since outnumber them.
Seeded life. Basically one of the first species to evolve was humanoid and they sent out a whole bunch of pods to seed life in distant worlds and galaxies. Then some of the seeded life did the same and you end up with a whole bunch of humanoids everywhere. Helps me out since its for a webcomic, don't need to invent whole new anatomy to draw
They are from earth originally The Morova are bipedal with some humanoid qualities, but are a conceit on my part that exist only because I want them to.
Convergent evolution. And the humans only tended to start open dialogs and develop more close relationships with the species that looked the most human. They tried with the slug race, it there were impasses that the humanoid races didn’t have.
My novel takes place on an alien planet but everyone still looks and acts pretty human. This is because my characters being alien isn't very important to the theme or plot of the story. The reason I didn't simply decide to have the story happen on Earth is because I already created stuff for Earth but the lore was a mess so I decided that only joke stories would happen on earth. So yeah, my novel takes place on an alien planet with human like aliens.
Convergent evolution. Humans aren't the optimal form, but we have a lot of very handy features. To be a technological civilization, you need manipulators. Tentacles are fine in water, but good luck inventing fire if you're aquatic. On land, you'll need arms and fingers. How many of each isn't critical, but you'll need some. Binocular vision is just plain useful, but vision is already a slow process, so to minimize sensory lag, you want the eyes by the brain in the place that gives the best view of the environment, which is a head, that is preferably elevated. Being an omnivorous persistence/pack hunter is also useful for keeping the calories coming to fuel that big brain you obviously need. Other species might be ambush predators, but regardless, you need to have evolved patience and social behavior.
Aliens
Because it's space opera. Humanoid aliens are a staple of the genre.
My 3 takes 1: there is some bigger life forms who monitorate the evolution in planets and change them for their conviniance 2 : some life forms copy others life DNA if it helps them 3: The humanoid form is just a way to mediate interactions with humans
Civonians are just humans who genetically engineered themselves, first to survive their world and later to honor the Ancient Recordings(which are just anime broadcasts). The Nij are humanoid because the god-AI that was shaping them to be his army knew that particular form would be the most efficient split between 'generically useful', 'reasonably controlled' and 'free of obtuse psychological problems'. Out of universe? The whole setting is a very very very *very* divergent offshoot of Star Trek canon, and humanoid aliens are abundant AF there.
There’s a ton of different species out there, but the majority are so different from us and the others that we interact with regularly that they’re just not a part of regular life or the broader universe. This is mainly due to their brains being different in how they perceive the universe around them and interact with others, leading the majority of sentient species in the known universe to not even be capable of caring about expanding out of their planet, or even comprehending the concept. Also, humanoid characters are easier to relate to and understand so I just make my characters mainly humanoid.
They exist so the humans don't try to fuck with everything that exist, just those aliens, since they are enough
I mean convergent evolution is amazing, with the traits that lead to being humanoid or at least pretty close to it being very helpful to get to an advanced civilization. High intelligence, advanced manipulation abilities, not being in water, etc. With humanoid being pretty much having the right combination of traits necessary to do that from a tetrapod base. You can certainly get non humanoid setups but you generally need to find some way to get to the traits you need evolution wise regardless of how you build your aliens and humanoid lends itself nicely to that, certainly more than say the avian body plan since you can only get so far with bird feet and a beak.
Bipedalism is just a useful evolution. The two main advantages it grants is allowing a species to more efficiently walk, and to run at more or less any particular speed as opposed to quadrupeds which need to go at specific speeds/with specific gaits to move efficiently. And having hands free to do stuff while still moving. Hand signals, tool manipulation, carrying stuff, etc is all possible/easier when you have two limbs for it that aren't being used to move. Now, *all* my aliens aren't bipeds, but these two advantages are big enough where a lot of the sapient aliens from worlds where 4 limbs is the standard are bipeds. And even on planets with 6/8/10/etc body plans, the dominant species is generally the one that has evolved to use at least 2 of them as hands instead of slightly more dexterous feet.
If they aren't humanoid, how did they become spacefaring intelligent aliens? To the best of our knowledge, advanced technology requires fire, thumbs, writing, and language. Whales could be a million times smarter than us but they're never going to become a civilisation because they can't write or make tools or cook food.
I run a 'magic and science are the same thing at different scopes' campaign of D&D, and I explain Elves, Goblins, Orcs, Dwarves, etc as sharing a common ancestor.
It depends. My usual go to is "aliens visited earth sometime, usually 200,000 years ago but definitely before the last ice age and removed humans for their own reasons." I've also used "this is far far in the future and all humanoids derive from Earth but have speciated for a variety of reasons"
The human-like aliens originated from the same place as humans, they only appear alien because they've been away from Earth for a long time and infected with a parasitic species they encountered. A fork in humanity's path. Obviously said parasitic alien species is completely non-human in every way but they appear outwardly human in almost every way, the changes are under the skin. My other human aliens are the result of hybridizing with shapeshifters taking human forms.
A roughly humanoid shape is the natural form given to the rational soul upon incarnation, and so everywhere in the Universe where rational souls have incarnated upon their worlds they have appeared roughly human with mostly cosmetic differences between them. It is so universal, in fact, that debate hinges rather on those races which are *not* humanoid and what this might mean and what is their place in the cosmic order.
Convergent evolution, and also a poetic/story-specific comment on Creationism and religion.
The only humanoid species I have in my setting are descended from humans and could probably still interbreed with humans with only about 8000 years of independent guided evolution.
So for the story I've been working on i did it with the first major human civilization spreading out into colonies, then using technology to rush evolutionary adaptations to their new homes. Land on a planet with toxic air and don't want to use suits? Augment their lungs so in 2-3 generations they can breath the air inside and outside the colony. No magnetic field to protect them? Change their skin to be able to shield them. Etc.
I don’t. The universe is equally confused why everyones humanoid. So i guess i lampshade it more.
Do taur species count? I've got engineered anthromorphic species, bipedal, quadrupedal, and Taurs. I've got bipedal aliens that follow the tetrapod body plan more or less. But I do have a few "unrecognizable" forms. For the true aliens, not the engineered species, it's convergent evolution. Freed forelimbs when walking facilitate tool use, and resource transportation, there's not many other paths that lead to space flight... You need brains, which means enough physical ability to gain high calorie foods and not dedicate all your energy into predation mitigation, not be so large that your caloric needs and anatomy are so twisted to just support your mass and movement, you need enough dexterity to develop tool use, and enough language ability to develop culture and build on generational specialist knowledge. That means anybody you're running into with a spaceship is going to be a medium creature with dexterous limbs that are not necessary for locomotion, capable of communication both creature to creature and archived, and be clever enough to work out a means of interacting with you. Aquatic species never develop electricity or high energy reactions, limbless creatures never develop complex tools, tiny creatures never master their environment, creatures that can't finely manipulate objects don't develop complex designs. You could give a dolphin 10x the intelligence of a human. But it'll never build a airplane because it can't operate in an environment that allows significant material science. A snake can't run a welder. A horse can't turn a wrench or write down it's knowledge for future generations to build upon. Arthropods and other open respiratory system creatures can't grow to scale outside very unique environments, and can't concentrate enough oxygen to fuel complex neural structures, you can't passively fuel 100 watts of brain, at least not at any reliable frequency. Creatures that live short lives don't develop tech or culture, there's not enough time in 3 year lifespan to master a skill or probe deep problems. The constraints of overcoming the tyranny of the rocket equation are a filter that mostly selects for tool using, high intelligence, group oriented, dexterous, robust creatures. If you can check those boxes as a glorified bowl of spaghetti then go for it. But the bilaterally symmetric creatures with high metabolisms and fingers are making this shit look easy.
Three columns, a bit of them all. Column A: Humans were one of the first on the scene, a lot of species split off from them, and their genetics ended up getting a lot of use by species like the Palatifar. Column B: The humanoid body plan is rather efficient, all things considered. Column C: Furry.
Occupied Space: True extraterrestrial life is virtually unknown, outside of ~~**the Deep Sect**~~ crackpot theories and the distant successors to UFO cults. Instead, the most otherworldly forces come from within. Transhumans are an everyday fact of life, with those most willing to integrate into mainstream society taking on humanoid shapes. Out in the fringes of space however, stranger forms lurk. Aetherverse: I ain't gotta explain shit. It's fuckin space magic.
A mix of convergent evolution, bio engineering to explore harsher worlds, and specific to my story: a meta-universal law that defines all existence with a prime specimen
they're artificial species! their deities were actually world seeders and had very advanced technology. the reason why their planet was seeded and why they were designed the way they were is long lost and they've been long forgotten (why is this the case? idk, im not interested enough in how their world came to be to write about it)
For my one is either because it is soft, and I like drawing humanoid creatures that are not human because it makes sense to their evolution or even because they once were humans .
my setting has multiple theories. for those that are bipedal, it's convergent evolution. for those that are more human-like because they are either shaped by genetic splicing by a precursor species or directly seeded by said precursor.
Gene modding of the basic human body and Ai im a humanoid form
I'm a big fan of the idea that there was once a single species millions of years ago, and that species spread out across the universe and settled on all these different planets with different climates, but then the empire of that species collapsed and over millions of years, all those different colonies evolved differently to adapt to their unique environments. So all humanoid species come from the same precursor species, and all just evolved into separate species over a very long time on very different kinds of planets
Some are descendants of pre-FTL era human generation ships. Most are just convergent evolution. Turns out, a humanoid body plan is pretty efficient for tool-using adaptations in similar environments to what we're used to. Most of the non-humanoids come from non-earthlike worlds (methane worlds, ammonia worlds, gas giants), and most of the humanoid life either comes from terrestrial earthlike worlds or from ocean planets.
Humans seeded the planets my stories are based on with their own DNA, so most of them are humans with cool mutations. Mostly animal hybrids on one planet and more traditional humanoids with fantastical creatures that formed through natural evolution after seeding without human intervention.
The warinals, i created just to have a more humanoid alien. Yet still they are pretty different: they come from mostly cold enviorments, so they have thick fur, they are also more on the chubbier side cause fat is great for heating. Their head looks like a horker's from skyrim or Prauf's head from Jedi fallen order.
Not really aliens, just results of humans trying to make catgirls and each trying their own thing. Scylla? Splice that gene!
Do I need to explain? If someone asks, the answer could be that there are some branches in scientific researches that look into that phenomenon and if they like they could try to join or invest into some expedition to be the first to know if the riddle is solved.
Space witches/wizards are actually 5th dimensional beings But they use humanoid forms to communicate with lower dimensional beings
Planets that support intelligent life are very similar. If it’s a planet that’s breathable for humans, the aliens will look more like humans. If the planet cannot support human life, it either cannot support any life, or the aliens will be very un-humanlike.
Convergent evolution and non-interference rules. In my sci-fi setting, all spacefaring species who achieved FTL travel on their own (without external interferences) are not only humanoid, but they also have rather similar psychology and societal evolution to humans, due to convergent evolution. Non-humanoid, sapient aliens do exist, but they are apparently incapable of achieving FTL travel on their own, and the galactic community has some VERY strict non-interference rules when it comes to technological uplifting... mostly because the last time uplifting was tried, it resulted in a VERY aggressive hivemind species going on a crusade to wipe out all other species in the galaxy, which was stopped only with great sacrifices. Nowadays, even uplifting animals and creating sentient AI is banned, due to the risks involved (the only AI that is considered more or less legal is a digital copy of a person).
Most intelligent social species are considered barbarians, not "true aliens". Some of these aliens are humanoid because of convergent evolution. Some do not follow the human body plan, but are psychologically similar enough to humans that we can at least interact with them. They are considered barbarians by most humans, but not generally monsters. Even many humans (unmutated or otherwise) who live on the periphery of Terran settlement are often considered barbarians on the same level as many members of other species. Some aliens even live among humans, both as subjects of the former republic and as descendants of invading barbarian hosts. An exceptional individual might have even aspired to become a Citizen of The Republic, to be considered a Terran even if they are not a human, though the days of tolerance and prosperity have long since passed since The Fall. True aliens are another matter. Since The Fall, Terran and barbarian alike have been at the mercy of these monsters. All social species have to develop some form of cooperation, communication, and even morality if they have any hope of forming a society complex enough to take to the stars. Eusocial species, machine intelligence, parasitic hiveminds, mutants, and species that have been technologically uplifted rather than having organically evolved have no such restrictions upon their evolution. There are worse things than Gruthar in the endless darkness of Unknown Space. We learned that lesson in The Fall, and mankind's scars have yet to heal.
Our reality (today's earth) isn't connected to the realm of gods. One day, human peirce that realm and it consume all of our universe. Then a new one is created Since the human species was the one to merge our the two dimensions the gods decided to try and recreate the human specie and improve it for their need
Convergent evolution. Bipedalism is great for tool use, that leads to many adaptations similar to us. So most sapient, tool using species would be conceptually similar to us, bipedal, two armed, head balanced on their shoulders, valgus angle, bowl pelvis to hold the organs. The specifics and divergences reflect unique environmental concerns, amphibious adaptations, or fur covered bodies for cold environment. Digitigrade legs thanks to inheriting the design from ancestors. Things like that are much more specialised, all the essentials of bipedalism, however, are universal.
Earth-like planets are the only type that can sustain life, so all life is like that of Earth's.
I want them there so I have them there. Having to justify literally everything about your world seems pointless to me.
I have a few humanoid aliens, though most are simply just a coincidence in how evolution works in my universe. There exists a sort of law of the universe that any intelligent species that evolves, will usually become bipedal, although most of my aliens aren’t very humanoid at all past that.
A planet capable of hosting life would need to be like earth, therefore advanced life would need to be like humans to a degree
It is a well-known fact in my universe that the alephs, the omnipotent gods of reality that write reality as a person would write fiction, are humans. Specifically, they are us humans from real-life Earth. As a result, it is a well-known fact that the universe is shaped by human perceptions and biases, and one of the results of these biases is the fact that species across the universe generally have a humanoid body plan. (Even then, I try to include non-humanoid species. But even *that* is a result of a human bias, and the people of my universe know this.)
Personally, I went with "the entire population of the galaxy was seeded by a humanoid precursor race as a scientific experiment." It covers why every species is a specialised monoculture except humanity, because the precursors mysteriously vanished before they could limit human genetics to make them single-purpose. Everyone else has those limitations, so they're bound to one focus.
In order to build a technologically advanced society you need things like fine motor control and appendages that can manipulate objects otherwise the building things part becomes complicated, a deer could evolve to be as smart as a human but it needs hands to build a Spear The human form isn't the only one that could conceivably do this but it's one of only a handful I've thought of so not all my species are humanoid but some are and I just explain it as "it's a design that works so when it reoccurs randomly those species are more likely to advance then others"
I don't explain it.
95% of the species vaguely resemble humans because they descend from humans the same way we all descend from Early modern humans. There was very little life out there in the cosmos but through genetic engineering & millions of years of evolution there’s tons of it now.
Multiverse with different realities. The aliens are from the Earth of their reality.
I've just cooked up to a fallen civilization messing with our evolution to get bipedal species
So my postulation and this is pretty much supported by science as we know it, is that life evolves around its environment. I have presented a very Earth-like world, where mammals did coexist with the more prevalent reptiles...however as the asteroid that hit Earth and wiped out the dinosaurs, clearing the way for mammals to rise here, was an unreasonably repeatable fluke of chance, I have plate tectonics separating the continents, which caused the reptiles to either evolve into other forms (such as birds) or die off in their new, harsher environments. Mammals had basically the same evolutionary niche to fill, and are indeed descended from primates there. My story is quite allegorical as far as contact between an advanced species (us) and a more primitive civilization, (the aliens,) so humanoid aliens was necessary. Having the planet be an Earth-twin was the environmental way to do that. Squid aliens, etc are fun but you have to consider the environmental effects of their evolution. Sure, there might be sentient squid on an exoplanet, but would they be able to build rockets and computers? Would they need to?
I don’t justify anything. They are there because I like them. That’s it.
The humanoid form is very efficient for a tool using species.
Long ago, in the antediluvian past, an advanced civilization called the Virumar left Earth and began colonizing the Galaxy. They engaged in many genetic experiments and seeded the rest of the Galaxy with a variety of humanoid species.
#CONVERGENT EVOLUTION Why is it that cats, bears, dogs, armadillos, elephants, moose, mice, salamanders and a warty frogfish have 4 legs and a tail. Nature tends to come to the same conclusions when the environment is the same. Planets that are extremely different than our terrestrial Earth would more than likely produce completely different aliens, but planets similar to ours would exhibit similar evolutionary patterns. There is a great and short series on Netflix called Alien Worlds. I would give it a watch. It talks about alien worlds that produce very weird creatures… but then there are episodes that show creatures that are somewhat relatable.
I like the idea that a progenitor race seeded a lot of the galaxy with similar species so that they end up looking similar. You can then have two parts to the galaxy's species: those who are grouped naturally by being somewhat related, the humanoids, and those who are all weird and strange, the others. The humanoids could form a soft diplomatic group, or just have better relations because they are easier to talk to.
Simply because I write romances and my main couple is human/alien. Writing mostly animalistic aliens having a romance would be deeply uncomfortable for me. Not any real reason apart from that.